8mm Forum: JOHN WHITTLE ... Please Help!!

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Posted by Osi Osgood (Member # 424) on March 27, 2008, 07:46 PM:

Hey John,

Are you the gentleman who was mentioning recently about a guy who reportedly a come up with a formula for fading prints and had registered for a patent for his idea?

If so, could you please e-mail me with all the details, as i would love to either contact him, or read up on his research on the internet, so that perhaps I could come up with the formula to help a few of my aging optical sound Super 8mm?

Thanks ahead of time.

OSI

Posted by John Whittle (Member # 22) on March 27, 2008, 10:31 PM:

You can do a search either at the us patent office or with google patents. I printed that out several years ago and can't put my hands on it right now. Suffice it to say it didn't work and I don't think the inventor is still with us.

If such a thing did exist, Kodak would certainly have licensed it. The idea is quite simple (and even sound). The cyan dye changes chemically to a clear substance and the idea is to convert it back to the dye.

There are other techniques which do work with magnetic tapes which shed or stick which can be baked and then become usable for a period of a few hours, long enough to re-record the material off of them.

In the case of film it might be that the change would last long enough to make a new print or do a telecine transfer.

John

Posted by Dan Lail (Member # 18) on March 27, 2008, 10:48 PM:

John, that's very interesting. Funny you should mention audio tapes. I have many hours of tapes I have made going back to the 1970's that are now suffering from "sticky shed" syndrome. Seems the only ones to survive are the BASF tapes. There is a company in The Netherlands called RMG International that sells a new formula tape(SM 911) that will not develope "sticky Shed". You can purchase a food dehydrator at Wall Mart that will hold a couple of reels of tape. You bake them at 130 degrees for a few hours and there good to go for about 30 days.

Posted by John Whittle (Member # 22) on March 28, 2008, 09:50 AM:

Dan,

With audio tape and old 2 inch video tape, there are differnt times and temps for different tape. It depends on the tape, the width, etc. It seems these failures are similar to vs on film.

If I recall correctly, a one hour 2 inch quad video tape baked at 250 degrees F for 20 to 30 minutes and then should be re-recorded with in 24 hours--that "fix" such as it is, doesn't last.

John

Posted by Osi Osgood (Member # 424) on March 28, 2008, 10:23 AM:

I always had this wild idea, (and still, sometimes tempted to do with a piece of unwanted scrap film) of creating a tank of whatever dye seems to have disappeared on the film, (for instance, blue), but I always needed someway for the dye to permeate the film, and that agent escapes me, but if I could figure out the agent to allow "permeation" of the film, I might have a go at it.

Posted by John Whittle (Member # 22) on March 28, 2008, 01:46 PM:

What you'd be doing in effect is "tinting" the film and you'll get an overall cast just like putting a filter in the projection beam. BTW you can use food coloring with water and a little photoflow (Kodak's wetting agent which is just a super detergent)for your test.

What you need to do is come up with a chemical that "couples" to the dye molecule and reforms it to a light changing rather than a clear substance.

Good luck, a lot of organic chemists in photo research around the world have worked on finding this. There was a lab paper that came out from 3M/Ferrenia which detailed the fading process and what happened to the cyan dye.

The problem with the coupler is they are often destroyed in processing. A coupler by the way is that thing that links the silver halide to the dye such that only the amount of dye is released that is proprotional to the silver halide exposure.

The patent refered to earlier used a vapour and then a "light" of some sort to fix the reconstructed molecule. A nice dream, but as I said it was never demonstrated so like a lot of computer software it was only a dream (vapour ware).

John

Posted by Osi Osgood (Member # 424) on April 01, 2008, 10:29 AM:

Hey John, another question that occured to me ...

Would different film stocks respond differently,to different approaches, or perhaps, different solutions ...

... or, are film stocks fairly "universal" in chemical approaches?

I ask as, perhaps my Kodak SP would respond better to chemical color reversal, than the dreaded Eastman color stock. Perhaps that mid 70's Eastman stock, (which tended to fair much better),
would respond better as well?

Any thoughts John (and others)?

Posted by John Whittle (Member # 22) on April 03, 2008, 05:22 PM:

Kodak originally used different couplers and developing agents from Fuji and Agfa. Eastman used CD-3 for Eastman color negative and Ektachrome, CD-2 for Eastman color positive. When the patents expired in the mid-70s on these chemicals, Agfa and Fuji introduced stocks that used the same processes which made if possible for a lab to use any of the three color positive materials in a single processing machine. Agfa Gevacolor and Gevachrome used a totally different suspension system and a different color developer and coupler.

This does not mean that the dyes used in the various stocks was the same. Agfa used a different cyan dye and since it had a better absorption in the infrared spectrum, it made a better optical sound Super8 print that Eastman material.

And dyes were changed with various stocks (5282/7382, 5385/7385, 7380, etc) in both the Eastman line and Agfa.

There were also various suppliers of chemicals and labs could buy from Kodak (for CD-2) or Hunt (for Code-2) for color developers. I don't know of any research or any record keeping that would allow us today to track chemistry against fading.

There are just so many variables from so many labs that we'll never know for sure if one is more stable than another.

What we do know is that films that have no resuidal couplers in the emulsion have much better keeping qualities. These are Technicolor IB prints which were dye transfer and Kodachrome which had the couplers in the processing baths and not in the film. The dyes in Kodachrome and processng also changed over the years (as did the film base which was different than that used for Eastmancolor) so there can be differences between a Kodachome from 1940s, 1950s, 1960s into the 1970s. The films also got faster, finer grain and sharper over the years.

John

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